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Ask HN: What indoor CO2 monitor do you recommend?

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Re: Ask HN: What indoor CO2 monitor do you recommend?

#61

Post by troydavis »

phinnaeus wrote: post #6

I picked up a pair (indoor+outdoor) of https://www.airgradient.com monitors a few months ago. Happy with them so far though I have not decided on their final positions.

I bought an AirGradient indoor meter and ran into 3 significant undocumented problems, 2 of which affect CO2:

1. The VOC readings use a relative scale and it's relative to a floating value: the last 24 hours. If a VOC source is present for more than 24 hours, it will quietly become part of the baseline value (100). You can read more here: https://forum.airgradient.com/t/measurement-values-for-the-a... , https://forum.airgradient.com/t/measurement-values-for-the-a...

2. The CO2 measurements re-calibrate to the lowest value detected every week (as ~400 ppm clean air). If it's not exposed to clean air every week, the readings will drift. When users asked how this worked, calibration hadn't been thought about much, if at all: https://forum.airgradient.com/t/model-number-for-co2-calibra... , https://forum.airgradient.com/t/model-number-for-co2-calibra...

3. The graphs don't show reboots, even though reboots (always?) reset the baselines. Reboots happen relatively frequently due to software updates. So, even the relative scale can change without any entry on the graph.

I was pretty annoyed because it didn't seem like the company had thought through the user experience enough to even encounter these questions, let alone consider the best implementation (or at least document the flaws in whatever they're able to implement). This is the whole purpose of the product. The company means well and tries hard, but at some point good intentions matter less than the product.

Re: Ask HN: What indoor CO2 monitor do you recommend?

#62

Post by leemck »

The AZ-0001 Co2 meter. Vendor of a CO2 meter with zero to 2000 ppm co2, 30 or 50 ppm accuracy, serial data output, humidity, and temperature. The meter appears on a big name cheap sales website for a little under $200.

https://www.co2meter.com/collections/handheld/products/az-ha...

One problem with the yellow AZ-0001 CO2 meter is the meter has to be manually restarted if the 9 volt input DC power is interrupted. A second problem is the CO2 value is quite sensitive to my breath when the meter is running on the garage workbench. For outdoor readings the mechanical problem is to put the meter at least 8 feet away from passing humans and also have the meter accessible for restarting.

The same vendor sells a hockey puck device which I have also used. I stopped using the hockey puck due to it's humidity measure device. That was about 4 years ago.

https://lessco2essay.blogspot.com/2015/08/carbon-dioxide-met...

Contact me for a copy of my Python CO2 meter software. The output of the software is lines of unixtime, GPS position, CO2, humidity, and temperature. leemck at gmail dot com.

My CO2 interest is in the global excess CO2 problem.

Re: Ask HN: What indoor CO2 monitor do you recommend?

#65

Post by LUmBULtERA »

kkfx wrote: post #58
forbiddenlake wrote: post #57

Earlier quoted context omitted.

Please, define your acronyms on first use. I read all that and still had no idea what you were talking about. But the context was enough to search. VMC stands for controlled mechanical ventilation in French.

Sorry, seems to be the common name in many countries, not just in France and Italy and I do not know any specific translation. In more broad terms a modern home is composted of: - a compact design to minimize surface dispersion of heat, a sphere would be ideal but obviously it's not much practical so we tend to the "cube" instead; - aligned to the north-south axe to maximize the Sun intake in winter, so with more or…

Thanks for all the info! It's not necessary to avoid acronyms or initialisms, just the first time it is used put what it is short for in parenthesis. For example, Federal Bureau of Investigation (FBI), then you can use the FBI in the rest of the text.

Re: Ask HN: What indoor CO2 monitor do you recommend?

#66

Post by moooo99 »

crazygringo wrote: post #37
licebmi__at__ wrote: post #33

Genuinely curious, what are the advantages of a CO2 monitor? I mean, I get you can “track air quality” but what exactly does that mean on day to day basis?

It means you know when to open the windows more to maintain fresh air. I think much better and am in a better mood when CO2 levels are lower, or when air is fresher generally (the two generally correlate). But I don't want to keep my windows wide open all the time because that wastes AC or heat. So if the monitor is reading above 650, I open windows a little bit. If it's reading over 800, I open them wider. If it's u…

I‘m genuinely curious, but isn’t a CO2 sensor an unnecessary high tech solution considering you could just open your window once a day for a few minutes and let the air exchange?

Re: Ask HN: What indoor CO2 monitor do you recommend?

#67

Post by ahaucnx »

troydavis wrote: post #61
phinnaeus wrote: post #6

I picked up a pair (indoor+outdoor) of https://www.airgradient.com monitors a few months ago. Happy with them so far though I have not decided on their final positions.

I bought an AirGradient indoor meter and ran into 3 significant undocumented problems, 2 of which affect CO2: 1. The VOC readings use a relative scale and it's relative to a floating value: the last 24 hours. If a VOC source is present for more than 24 hours, it will quietly become part of the baseline value (100). You can read more here: https://forum.airgradient.com/t/measurement-values-for-the-a... , https://forum…

Achim, founder of AirGradient here.

These are all valid points that came up at the beginning of the year and we took this feedback very seriously.

I'm happy to let you know that we have implemented already point 1) and 2) in the latest firmware version.

You can now set the "learning gain offset" for TVOC and NOx from the default 24h to basically 1 year. As a result the monitor will behave much more like an absolute TVOC monitor as the baseline reset is much longer.

We have also implemented the automatic baseline calibration period, which you can now set to a much longer period than one week.

We are also looking into feeding the last vale back into the sensor to avoid the reboot issue but this is more tricky to implement.

By the way, if you compare the granularity that we offer now to fine tune the sensor modules, I'm not aware of any competitor offering the same feature set. But we won't stop here. We currently working on fine tuning compensation algorithms for PM.

Re: Ask HN: What indoor CO2 monitor do you recommend?

#68

Post by ahaucnx »

mtlynch wrote: post #42
phinnaeus wrote: post #6

I picked up a pair (indoor+outdoor) of https://www.airgradient.com monitors a few months ago. Happy with them so far though I have not decided on their final positions.

I also own an indoor AirGradient, and I like supporting open-source, open hardware, but I've been pretty disappointed with the product. There were no instructions in the box, and I had to dig around a while until I found this PDF from three years ago.[0] I normally can figure out a gadget without reading instructions, but this wasn't self-explanatory, as there are no inputs on the device itself, and I had to figure o…

Achim from AirGradient here. I fully understand your frustration.

Maybe a bit of background information to put this into perspective.

Until around a year ago, the open-source DIY kits where a seperate 'side project' as we focused on our (now retired) closed source air quality monitors.

However last year we decided to go fully open-source hardware and started to merge the closed source features into the open-source firmware. Because we needed a much better code base, a complete re-write was required (also supporting two different MCUs).

So the last 6 months was really a transition period and things were a bit messy but I believe we have a much better onboarding and instructions [1] now available on the website and are continuing to work on it.

[1] https://www.airgradient.com/documentation/

Re: Ask HN: What indoor CO2 monitor do you recommend?

#69

Post by mtlynch »

ahaucnx wrote: post #68
mtlynch wrote: post #42

Earlier quoted context omitted.

I also own an indoor AirGradient, and I like supporting open-source, open hardware, but I've been pretty disappointed with the product. There were no instructions in the box, and I had to dig around a while until I found this PDF from three years ago.[0] I normally can figure out a gadget without reading instructions, but this wasn't self-explanatory, as there are no inputs on the device itself, and I had to figure o…

Achim from AirGradient here. I fully understand your frustration. Maybe a bit of background information to put this into perspective. Until around a year ago, the open-source DIY kits where a seperate 'side project' as we focused on our (now retired) closed source air quality monitors. However last year we decided to go fully open-source hardware and started to merge the closed source features into the open-source fi…

Hi Achim, thanks for the response!

Would it be possible for you to document somewhere how to flash from source? The website currently kind of explains it under "Flashing Of The AirGradient Firmware," but step two is to flash the "ONE_V9.ino" file, but there's no explanation of where to get that file.

I know it used to exist on AirGradient's Github[0], but now I don't see it anywhere after the v3 rewrite.

[0] https://github.com/airgradienthq/arduino/blob/2.4.15/example...

Re: Ask HN: What indoor CO2 monitor do you recommend?

#70

Post by ahaucnx »

mtlynch wrote: post #69
ahaucnx wrote: post #68

Earlier quoted context omitted.

Achim from AirGradient here. I fully understand your frustration. Maybe a bit of background information to put this into perspective. Until around a year ago, the open-source DIY kits where a seperate 'side project' as we focused on our (now retired) closed source air quality monitors. However last year we decided to go fully open-source hardware and started to merge the closed source features into the open-source fi…

Hi Achim, thanks for the response! Would it be possible for you to document somewhere how to flash from source? The website currently kind of explains it under "Flashing Of The AirGradient Firmware," but step two is to flash the "ONE_V9.ino" file, but there's no explanation of where to get that file. I know it used to exist on AirGradient's Github[0], but now I don't see it anywhere after the v3 rewrite. [0] https://…

It's now called "OneOpenAir.ino". We are still in the process to update the help files.
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